title: Biosorption of uranium by melanin: kinetic, equilibrium and thermodynamic studies.
abstract: Limitation of conventional techniques for the removal of heavy metals present at low concentrations, has led to the need for developing alternate technologies like biosorption. In the present study we describe the use of melanin pigment synthesized through green technology, for sorption of uranium from aqueous system. Biosynthesized melanin showed good uptake over a broad pH range. Removal of uranium was rapid and equilibrium was reached within 2h of contact. It was observed that the kinetic data fits well into Lagergren's pseudo-second order equation. A maximum loading capacity of 588.24 mg g(-1) was calculated from Langmuir plot. Thermodynamic studies performed revealed that sorption process was favorable. Binding of uranium on the surface of melanin was confirmed by FT-IR and energy dispersive spectroscopy (EDS). Thus, biosynthesized melanin can be efficiently used as a sorbent for removal of uranium from aqueous solution.
authors.affiliation: Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India. Electronic address: saini_amardeepsingh@yahoo.co.in.
authors.forename: Amardeep Singh
authors.initials: AS
authors.lastname: Saini
authors.forename: Jose Savio
authors.initials: JS
authors.lastname: Melo
mesh_terms: D000327:Adsorption; D031056:Amorphophallus / Q000378:metabolism; D001673:Biodegradation, Environmental; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D008543:Melanins / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D010316:Particle Size; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D013997:Time Factors; D014501:Uranium / Q000302:isolation & purification*
chemical_list: D007477:Ions; D008543:Melanins; D014501:Uranium
keywords: Amorphophallus campanulatus; Biosorption; Biosynthesized melanin; Uranium